Answer:
Square brackets will always be used, to enclose or group several arithmetic operations that involve several simultaneous operations, as described in the example.
The bracket generally groups or implies that the most particular or small operations must be performed until finally breaking it down and thus solving the entire general operation.
Explanation:
1. When there are no parentheses or square brackets, we do the multiplications and divisions first if there are any. If there are several positive and negative numbers we group them together and then add them together.
2. When there are parentheses, we first make the calculations for the parentheses if there are any, and then to remove the parentheses we apply the rule of signs, sign that is in front of the parenthesis for each sign that is inside.
3. When there are parentheses and square brackets, we make the parentheses first, we remove them applying the rule of signs. Then we make the brackets and remove them applying the rule of signs. Then we make the products and divisions and finally the sums.